1. Field of the Invention
The present invention relates to a bending operation mechanism having a watertight structure and an endoscope including the bending operation mechanism.
2. Description of the Related Art
Recently, endoscopes have widely been used in the medical field and the industrial field to examine and treat a cavity and a hollow organ of the body. These endoscopes include a thin elongated insertion section to be inserted into the cavity and hollow organ of the body. As the insertion section, a flexible scope bent in accordance with the bending state of an insertion path and a rigid scope used chiefly for operations and the like are known. The flexible scope includes a bending section at its distal end, and the bending section can freely be bent in a desired direction in accordance with a user's hand operation.
As disclosed in, for example, Patent Literature 1: Jpn. Pat. Appln. KOKAI Publication No. 2009-89955, as a conventional endoscope, an endoscope is known in which a user tilts a joystick-type operating lever provided on an operating section toward an arbitrary direction to pull an operating wire and render a bending section in a desired bending state.
In medical endoscopes, an insertion section used in a body cavity has a watertight structure to prevent water drops and blood from entering the body cavity, and an operating section, which is formed integrally with the insertion section as one unit, needs a reasonable watertight structure to irrigate and sterilize the operating section after it is used.
The conventional endoscope including a joystick lever type operating section is so configured that even though a joystick lever is tilted to any position within a movable range of the joystick lever, the water-tightness between the joystick lever and the exterior member is always secured and the lever operation is not inhibited. For example, Patent Literature 2: Jpn. Pat. Appln. KOKAI Publication No. 2004-321612 discloses an endoscope in which a joystick lever portion is covered with an elastic cover member (e.g. rubber cover or a rubber boot) which is fitted into a central hole in a watertight manner and the peripheral edge portion of the boot is pressed and fixed on an operating section exterior member by a substantially ring-shaped fixing member. With this structure, the operating section secures its water-tightness and the flexible rubber boot is deformed when the lever is tilted, with the result that the bending operation can be performed comfortably without inhibiting the lever operation.
Accordingly, it is an object of the present invention to provide an endoscope which prevents an elastic cover member of a joystick-type operating section from being twisted when the elastic cover member is fixed on the main body of the operating section and prevents the elastic cover member from being entangled when a joystick lever is operated. In addition, it is an object to provide a small-sized light bending operation mechanism having a watertight structure and an endoscope having the bending operation mechanism.
According to the present invention, it is an object to provide an endoscope which prevents an elastic cover member of a joystick-type operating section from being twisted when the elastic cover member is fixed on the main body of the operating section and prevents the elastic cover member from being caught when a joystick lever is operated. In addition, it is an object to provide a small-sized light bending operation mechanism having a watertight structure and an endoscope having the bending operation mechanism.